Separator and preparation method thereof, battery cell, battery, and electric device

Abstract

A separator and a preparation method of separator, a battery cell including the separator, a battery including the battery cell, and an electric device including the battery, where the separator includes at least two base films and a functional layer interposed between two adjacent base films, and the base film includes at least two components.

What is claimed is: 
     
         1 . A separator, comprising at least two base films and a functional layer interposed between two adjacent base films, wherein the base film comprises at least two components. 
     
     
         2 . The separator according to  claim 1 , wherein the base film comprises at least two film layers with each film layer comprising at least two components. 
     
     
         3 . The separator according to  claim 2 , wherein two to four film layers are provided with each film layer comprising two to four components. 
     
     
         4 . The separator according to  claim 1 , wherein a thickness of the base film is 3 μm to 15 μm. 
     
     
         5 . The separator according to  claim 4 , wherein:
 a porosity of the base film is 30% to 70%; and/or   a pore diameter of the base film is 100 nm to 800 nm; and/or   an areal density of the base film is 2 g/m 2  to 10 g/m 2 .   
     
     
         6 . The separator according to  claim 1 , wherein the components comprise at least one of polyolefin, polyether, polyetheretherketone, polyimide, polyethylene-propylene copolymer, polyvinylidene chloride, or fluorocarbon compound. 
     
     
         7 . The separator according to  claim 6 , wherein the fluorocarbon compound comprises at least one of polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, or polyvinylidene difluoride. 
     
     
         8 . The separator according to  claim 1 , wherein the functional layer comprises at least one of inorganic functional material and/or organic functional material. 
     
     
         9 . The separator according to  claim 8 , wherein the inorganic functional material comprises at least one of Al 2 O 3 , AlO(OH), SiO 2 , TiO 2 , MgO, CaO, BaSO 4 , Mg(OH) 2 , SnO 2 , ZnO, ZrO 2 , Y 2 O 3 , NiO, CeO 2 , SrTiO 3 , BaTiO 3 , or MgF 2 . 
     
     
         10 . The separator according to  claim 9 , further comprising:
 a bonding layer, wherein the bonding layer bonds the functional layer and the base film.   
     
     
         11 . The separator according to  claim 10 , wherein a weight percentage of the inorganic functional material is 30% to 50%, D v 50 is 0.2 μm to 1.2 μm, and a weight percentage of the bonding layer is 10% to 20%. 
     
     
         12 . The separator according to  claim 8 , wherein the organic functional material comprises at least one of cellulose, a derivative of cellulose, polyolefin, polyamide, polyethylene terephthalate, polyvinylidene difluoride, polyacrylonitrile, polymethyl methacrylate, or polyethylene oxide. 
     
     
         13 . The separator according to  claim 1 , wherein a thickness of the separator is 5 μm to 30 μm. 
     
     
         14 . A preparation method according to  claim 1 , comprising:
 performing electrospinning through at least two dispensing structures to obtain a base film, and interposing a functional layer between two base films to obtain the separator.   
     
     
         15 . The preparation method according to  claim 14 , wherein an electrospinning device used for performing electrospinning through the at least two dispensing structures comprises any one of dual-needle electrospinning device, multi-needle electrospinning device, rotating disk electrospinning device, conjugate electrospinning device, or needleless electrospinning device. 
     
     
         16 . The preparation method according to  claim 15 , wherein performing electrospinning through the at least two dispensing structures to obtain the base film comprises:
 feeding an electrospinning solution into the dispensing structures using a top-down or lateral liquid supply method, so that electrospun fibers are collected on a substrate; and then removing the substrate to form the base film.   
     
     
         17 . The preparation method according to  claim 16 , wherein a spinning rate of the electrospinning device is 0.5 ml/h to 2 ml/h, an environmental humidity is less than or equal to 30%, and a voltage is 15 kV to 20 kV. 
     
     
         18 . A battery cell, comprising the separator according to  claim 1 . 
     
     
         19 . A battery, comprising the battery cell according to  claim 18 . 
     
     
         20 . An electric device, comprising the battery according to  claim 19 .